On June 29, Sharpe declared a mistrial after jurors failed to reach a unanimous verdict in the trial of the Kenosha truck driver. He had been charged with first-degree intentional homicide in the death of Beck, a Sturtevant woman who left her Racine-area home on July 17, 1990 and headed to Appleton for a work-related seminar.

Beck stopped at a Fond du Lac mall, where authorities say she was abducted. Her van was found a few days later, and her body was discovered about six weeks later in a ditch along a rural road in western Fond du Lac County.

"The government, like the defendant, is entitled to resolution of the case by verdict from the jury and jeopardy does not terminate when the jury is discharged because it is unable to agree," the prosecutors argued in a three-page filing. "Regardless of the sufficiency of the evidence at a defendant's first trial, a defendant has no valid double jeopardy claim to prevent his retrial."

Sharpe scheduled a Sept. 6 hearing to consider arguments on whether Brantner's second trial will proceed. Brantner remains incarcerated in the county jail, where he has been held since his March 2015 arrest.

During the June trial, the prosecution established that Brantner resided in nearby Brandon, Ripon, Green Lake and Waupun during the 1970s and 1980s. One of his former jobs as an over-the-road trucker often put him in close proximity to Brown Road, where Beck's body was dumped.

Some aspects of the prosecution's case had holes. The Fond du Lac County Sheriff's Office either lost or discarded several noteworthy murder clues over the years that could have either proven Brantner's guilt or pointed to a different suspect.

"There was no direct evidence linking Brantner to Beck's death," Powell argued in his 15-page motion. "The state's entire case rested on the fingerprints. No witnesses implicated Brantner in the killing. No physical evidence tied Brantner to the killing. The only potential evidence that could have done so (the remnants of the red shirt and the pantyhose) were lost or destroyed by the state. No evidence establishes that Brantner was in Fond du Lac when Beck disappeared."

Powell contends that retrying his client for Beck's murder amounts to double jeopardy. "Brantner did not implicate himself in the crime through his statements to police or to anyone else," Powell reminded Sharpe. "At best, the state's evidence established that Brantner was inside Beck's van on July 17, 18 or 19, 1990."

Powell cited the 2001 exoneration of Green Bay paper mill worker Mike Piaskowski to justify his position that Fond du Lac County prosecutors don't have sufficient evidence to sustain a conviction against Brantner.

In 1995, Piaskowski was one of six coworkers at the James River Paper Mill tried and convicted by a jury of murdering Tom Monfils, a fellow worker, whose body was found at the bottom of a pulp vat.

Six years after his conviction, a federal appeals court overturned Piaskowski's conviction and he was freed.

"The court rejected the state's circumstantial evidence as conjecture, insufficient to support a conviction," Powell argued in his motion.

"Similarly, the state's evidence, at best, merely places Brantner in Beck's van around the time that she disappeared; it does not and cannot place him there at the same time as Beck or when she died, nor does the state's evidence establish where within the 450-plus (mile) radius of Fond du Lac that Brantner's prints were left in the van."

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Mike Piaskowski was exonerated in 2001 after the federal courts determined there was not sufficient evidence to convict him in the 1992 murder of a Green Bay paper mill worker, Tom Monfils.(Photo11: USA TODAY NETWORK-Wisconsin)

To this day, one of the most perplexing mysteries is that Beck's abductor put 462 miles on her van's odometer between July 17-19, 1990. Beck kept a written log of her mileage because she was headed to a seminar. She was kidnapped at about 11 a.m., just off the highway between Milwaukee and Green Bay.

Powell contends that Brantner did not kill Beck, but said his client may have unknowingly interacted with Beck's killer.

In February 2014, Fond du Lac County Sheriff's detectives questioned Brantner in Kenosha about why his fingerprints were identified on several different objects.

Within Beck's van, Brantner’s fingerprints were found on:

A Burger King cup.

A cellophane cigarette wrapper.

Beck’s employment manual.

A mixing plate from a hair bleach kit Beck bought at the mall's Walgreens.

A passenger side window of Beck’s van.

Brantner denied killing Beck, but became emotional at times during the questioning.

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Berit Beck(Photo11: File/USA TODAY NETWORK-Wisconsin)

“In part of Brantner’s statements introduced by the state, Brantner described an encounter with an unknown, mustachioed man at the Brat Stop bar in Kenosha, during which the man bought Brantner a lot of drinks and got him extremely drunk,” Powell wrote in his filing with the judge. “Brantner told police he remembered waking up in the motel across the street still in his clothes with no memory of how he got there. Brantner could not say exactly when it happened, but the circumstances surrounding his description were consistent with when Beck went missing.”

For more than 20 years, Fond du Lac County authorities identified Craig Hron, a career criminal from West Bend, as their prime suspect in Beck's abduction and murder. Hron went to prison for robbing a bank in West Bend days after Beck's homicide.

In a key pretrial ruling, Sharpe restricted Powell from putting on an alternative suspect defense by claiming that Hron — not Brantner — was the more likely killer. But in light of testimony during the first trial, Sharpe said he might reconsider his earlier ruling.

According to Powell, the prosecutors "evidence did not exclude the possibility of a different actor responsible for Beck's death. There remains an unidentified fingerprint on the steering wheel column and male DNA on a toothpick left behind in the van. Importantly, though Brantner apparently left fingerprints all over the rest of the van and its contents, none of his prints appear on the driver's side of the van."

Retired Fond du Lac Police Detective Milt Swantz points to an area where Berit Beck’s van was located on an ariel photo held by Assistant District Attorney Dennis Krueger June 15, 2016 at the murder trial of Dennis Brantner, who is accused of killing Berit Beck in 1990. Doug Raflik/USA TODAY NETWORK-Wi, Doug Raflik/USA TODAY NETWORK-Wi

A collection of evidence sits on a table June 15, 2016 at the murder trial of Dennis Brantner, who is accused of killing Berit Beck in 1990. Doug Raflik/USA TODAY NETWORK-Wi, Doug Raflik/USA TODAY NETWORK-Wi

Benjamin Beck answers questions from the prosecution in a Fond du Lac, Wisconsin court room during opening day testimony of the murder trial of his sister Berit, who was killed in 1990. Dennis Brantner is on trial for the 26 year old crime. Tuesday June 14, 2016. Doug Raflik, Doug Raflik/USA TODAY NETWORK-Wi

Dave Beck, father of murder victim Berit Beck, was the first witness for the prosecution to take the stand in the Dennis Brantner 1990 murder trial in Fond du Lac Wisconsin Tuesday June 14, 2016. Doug Raflik, Doug Raflik/USA TODAY NETWORK-Wi